1. Field of the Invention
This invention relates to a useful bath agent having the effects of eliminating and preventing skin itch and preventing skin aging. More particularly, it relates to a bath agent which contains sodium sulfate and/or sodium chloride and a free radical inhibitor and which is useful for eliminating and preventing itching and for preventing the aging of skin by preventing and removing effectively the free radical produced on the skin surface.
2. Description of the Prior Art
There have been known various bath agents so far. For example, the bath agents added with sodium sulfate and sodium chloride for the purpose of keeping the skin warm have been used from old times. There is also known a bath agent compounded of proteinases to wash off the waste matter of skin and the skin keratin [KOKAX (First Publication) No. SHO 58-59909]. Moreover, there are known a bath agent compounded of galenica or galenical extract for the purpose of anti-phlogistic effect and a bath agent compounded of kojic acid, its salt or L-ascorbic acid-2-magnesium phosphate For the purpose of preventing spots and freckles and becoming fair-complexioned [KOKAI (First Publication No. HEI 3-127724]
On the other hand, the free radical which produced on the skin surface by ultraviolet rays said to be the cause of itching or skin aging and progress into skin cancer in the worst case. Originally, there exists an enzyme, superoxide dismutase (SOD), in the skin which prevents the production of free radical on the skin surface. However, in case of the exposure to excessive ultraviolet rays or in case of the elderly having less SOD, the production of free radical cannot be prevented effectively. Therefore, in such a case a drug which removes the free radical produced on the skin surface is required.
Under such a situation, if there is a bath agent which has an action of preventing and removing effectively the free radical produced on the skin surface by ultraviolet rays and which can be used easily, it is considered to be convenient.
Generally, however, many free radical inhibitors are insoluble in water (for example, tocopherol, BHT, BHA) and water-soluble free radical inhibitors are hardly known. Although ascorbic acid, cystein, and glutathione which are water-soluble have strong reducing action, their inhibitory action is very weak if they have free radical-inhibitory action. Therefore, the action cannot be said to be fully satisfactory for the removal of free radical produced on the skin surface, which is the object of this invention.
Accordingly, bath agents having satisfactory free radical-removing effect [lave not been known so far under present conditions.
So the inventors made earnest investigation looking for useful bath agents to prevent and remove effectively the free radical produced on the skin surface. Consequently, the inventor unexpectedly found it possible to prevent and remove effectively the free radical produced on the skin surface by the combined use with sodium sulfate and/or sodium chloride and L-ascorbic acid tocopherolphosphate diester. This invention has been completed based on this new knowledge.